CA2136177C - Manufacture of terephthalic acid copolyamides - Google Patents
Manufacture of terephthalic acid copolyamides Download PDFInfo
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- CA2136177C CA2136177C CA002136177A CA2136177A CA2136177C CA 2136177 C CA2136177 C CA 2136177C CA 002136177 A CA002136177 A CA 002136177A CA 2136177 A CA2136177 A CA 2136177A CA 2136177 C CA2136177 C CA 2136177C
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
- C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
- C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids
- C08G69/28—Preparatory processes
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
- C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
- C08G69/26—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids
- C08G69/265—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from polyamines and polycarboxylic acids from at least two different diamines or at least two different dicarboxylic acids
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Abstract
A process for the copolymerization of (1) a carboxylic acid consisting of terephthalic acid and mixtures thereof with isophthalic acid with (2) a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine. The combined amount of isophthalic acid and 2-methyl pentamethylene diamine is controlled so that the resultant copolyamide, when annealed, has less than 1 %~by weight based on the total weight of the copolyamide of fractions having melting points greater than 320 °C. Preferably, the combined amount of isophthalic acid and 2-methyl pentamethylene diamine is greater than 27.5 %, molar basis, of the total amount of acid and diamine.
Description
~~.36177 ~~1'O 93/23454 PCT/US93/04486 MANUFAC:TURF OF TEREPHTHALIC ACID COPOLYAMIDES
The present invention relates to a process for the manufacture cf copolyamides of terephthalic acid, and especially tc the manufacture of such copolyamides without formation of a high melting fraction.
As used herein, a "single step" polymerization process is a polymerization process in which monomers are subjected to a polymerization cycle in a reactor that concludes with the pressure being returned to substantially atmospheric pressure. It is understood that the copalyamide obtained from such a process may be subjected to further processing, including finishing and extrusion, before or after pelletization.
Polymer~~ formed from terephthalic acid and diamines are known in the art. For instance, PCT patent application ~if0 92/10525 of S.L. Mok and R.U. Pagilagan, published 1952 June 25, discloses copolyamides of terephthalic acid with hexamethylene diamine and 2-methyl pentamethylene diamine, optionally containing isophthalic acid, having melting points of at least 280°C. Other polyamides of terephthalic acid are referred to therein.
Single-step polymerization processes have the advantage that polymer is manufactured in a single step, as opposed tc~ two step or multi-step processes, thereby reducing handling of the partially formed polymer during the intermed~~ate stages of the process. However, in the manufacture of copolyamides of terephthalic acid, especially copolyamides of terephthalic acid, hexamethylenea diamine and 2-methyl pentamethylene diamine, using a single step polymerization process, it has been found that a high melting fraction is formed.
The high melting fraction, with a melting point in excess of 320°C and especially approximately 334°C, is usually not noticed in the first batch of polymer produced in an autoclave, but becomes apparent in subsequent b~3tches made in the same autoclave without RCV. VOyI~YA ~1l_'~CIiE\ a 1 . _ _ ~ ='S'. 5-'~ _' ~ ~.~.43 ~ _ _ _ _ X10?
r7:3 :~85'>~ +-~9 8:3 '_:;~y94E~p : ii _8 Druckexernp~ar 2~3s~77 ~2~
steps being taken to clean-out the autoclave between consecutive batches.
As the polymer would normally be subsequently processed at melt temperatures of less than 320°C, the high melting fraction manifests itself as unmelted or gel-like portions of polymer, which are commercially unacceptable; t:ne gel-Ii:Ii;e portions arc believed to be essentially comprised of a high melting crystalline phase, which is soluble in sulphuric acid, and riot gel per sc whic:h WOLIId :not be soluble in sulphuric acid.
It ha,s now been found that copolymers of terephthalic acid, optionally including iso~phthalic acid, and mixtures of hexamethylene diarnine and 2-methyl p~entamcthylen~ diamine, may be manufactured without the formation of a high melting fraction in significant amounts.
Accordingly, the present invention provides a process for the preparation of a partially crystalline copolyamide comprising the polymerization stages of:
(a) feeding to a reactor an aqueous salt solution of an admixture of aromatic carboxylic acid and aliphatic diamine, said aromatic carboxylic acid being selected frorn the group consisting of terephthalic acid and mixtures of terephthalic; acid and isophthalic acid and said aliphatic diamine being a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine;
(b) heating the aqueous salt solution under pressure and venting water and other volatile; matter from the reactor;
(c) reducing the pressure in the reactor to atmospberie pressure;
(d) controlT,ing stages (b) and (c) so as to avoid excessive foaming of the admixture in the reactor; and (e) discharl;ing the copolyamide so obtained from the reactor;
wherein tl3e total amou nt of 2-methyl pentamethylene diamine and, when present, isopht:halic acid fed to the reactor in stage (a) is selected so that the copolyamide AMENDED SHEET
RC\ . 4U'yI.:YA \lt.W(:NE\ U 1 _ _ _ : ~~5-. 5-'J"1' _~ _ . lf'.:.'~'~ ~ _ _ _ _ 3t)'? . ~ ~ '3 ~''~'~'?" +4;3 F3:3 '?a3:3cy~~.~<~S : # _J -~~3617~
has less than 1%a by weight, based on the total amount of copolyamide, of fractions with melting lpoints greater than 320°C.
In preferred embodiments of the process of the invention, the stages of the process are controlled so that the copolyamide produced has an inherent viscosity of at least 0.6 dL/g, especially at least 0.8 dL/g.
In a further embodiment of the process of the invention, stage (c) additionally includes rroaintaining the admixture in the reactor under a vacuum.
In another embodiment, the acid and diamine are selected such that the total amount of 2-methyl pentamethylene diamine and, when present, isophthalic acid is greater than 27.5%, molar basis, especially greater than 30%, of thEe total amount of acid and diamine.
The present invention further provides in a process for the preparation of multiple: consecutive batches of a partially crystalline copolyamide of terephthalie acid and hexamethylene diamine in a reactor without clean-~~ut of the reactor, in which the copoiyamide obtained from such process contains more than 1% by weight of a fraction with a melting point of greater than 30°C, said process comprising the stages of:
(a) feeding; to a reactor an aqueous salt solution of an admixture of aromatic carboxylic .acid and aliphatic diamine, said aromatic carboxylic acid being seiectcd from the group consisting of terephthalic acid and mixtures of terephthalic acid and isophthalic acid and said aliphatic diarnine being a mixtur~: of hexa~rnethylene diamine and 2-methyl pentamethylene diamine;
(b) heating; the aqueous salt solution under pressure and venting water and other volatile: matter from the reactor;
(c) reducing the pressnrc in the reactor to atmospheric pressure;
(d) controlling stages (b) and (c) so as to avoid excessive foaming of the admixture in the reactor; and (e) dischar;giag the copolyamide so obtained from ANIEN~ED SHEEt RCV . ~ O\ _ ~Y:1 Hl; \C'lit.\ U 1 _ _ _ ~ ~'~-. S' 94 _' ~ ~~.'.'~'k' v _ _ _ __30~? .7 ~ '3 '~''~-'_ +4 9 ~3~,) '?:3;39-~~f;:i : N 10 the reactor;
the improven7:ent comprising reducing the amount of the fraction with a melting point of greater than 320°C to Less than 1% by feeding to the reactor an aqueous solution containing a total amount of 2-methyl pentamethyIene diamine and, when pr~;sent, isophthalic acid of greater than 27.5%, molar basis, of the total amount of acid and diamine.
In preferred embodiments of the process of the invention, the stages of the process are controlled so that the copolyamide produced has an inherem viscosity of at. least O.b dL/g, especially at least 0.$ dL/g.
In addition, the present invention provides in a process for the copolymerization of (1) a carboxylic acid consisting of terephthalic acid and mixtures therE;of with isophthalic acid with (2) a mixture of hexamethylene diamine and .;-methyl pentamethylene diamine, the improvement ' comprising controlling the total amount of isophthalic acid and 2-methyl pentamethyle~~e diamine so that the resultant copolyamide has less than 1%
by weight based on they total weight of the copolyamide c~f fractions having melting point'; greater than 3?0°C.
As used herein, "clean-out" of a reactor means steps takan to clean or remove high molecular weight polyamide, degradation or gel products and other matter that is not discharged from the reactor under normal processing conditions.
The; present invention relates to the manufacture of partially crystalline copolyamides formed from an aromatic carboxylic acid and a mixture of hea;amethylene diamine and 2-methyl pentamethylene dian:ine.
The aromatic carooxylic acid is terephthaiic acid or a mixture of terephthalic acid and isophthalic acid.
The: am~unt.s of acid and diamines should be substantially complernenta~y on a molar basis, as will be appreciated by persons skilled in the art. An excess of acids or diamines, especially the latter, may be used AMENDE~J ~HLE~
WO 93/23454 ~ ~ ~ PCT/US93/04486 _ 5 _ depending on 'the desired characteristics of the copolyamide a:nd the nature and extent of side reactions that may produce volatile or other matter; as noted below, diamines tend to be more volatile than acids.
The amount of isophthalic acid plus 2-methyl pentamethylene diam~ine is selected so that the copolyamide obtained has less than 1% by weight, especially less than 0.1% by weight and in particular less than 0.01% by weight, of fractions having a melting point of greater than 320°C. In preferred embodiments, the amount of isophthalic acid plus 2-methyl pentamethylene diaa~ine is selected so as to be at least 27.5%, molar basis, of the total amount of acid and diamine monomers. In more preferred embodiments, the amount of isophthal.ic acid plus 2-methyl pentamethylene diamine is at least: 30%, molar basis, of the total amount of acid and diamine~ monomers.
The copolyamicles produced by the process of the present invention acre generally partially crystalline polymers, rather than an amorphous polymer. In embodiments, the polymers have a heat of fusion of greater than 17 J/c~. Crystallinity may be determined using a differential scanning calorimeter.
The copolyamide is prepared in a polymerization process in which an aqueous salt solution of the aromatic carboxylic acids, hexamethylene diamine and 2-methyl pentamethylene diannine is fed to a reactor. The presence of 2-methyl pentamsathylene diamine appears to moderate branching that is understood to occur in a copolymer of terephthalic acid, isophthalic acid and hexamethylene diamine. The: molar amount of aromatic acid is substantially comp7lementary to the total molar amount of the diamines, as d:i.scussed above. As is known, diamines tend to be more volatile than carboxylic acids and thus it may be descirablee to feed an excess of diamine to the reactor. Cat:alyst:a may also be used e.g. phosphinic acid and/or the sodium or potassium salts thereof, phosphorus acid, hypophosphorous acid, sodium hypophosphite, RCV. VO'~_E.f'.~ ~II.WCHEV U1 _ __ ~~~5-. 5-'J'4 _:. .lE'.v.'~5 v _ __ __3lW ~
r3 aH5:1-. +.~y f3:3 '?.35~441iS:bl1 ~~.36177 ~6-phospborie acid and the; like; typical amounts of catalysts arc 0.05-L00%'o by weight, especially 0.10-0.20% by weight.
In the process, the aqueous salt solution is heated in a reactor (autoclave) under pressure. The actual pressure used will depend in part on the particular copolyarnidc that is to be produced in the process. In preferred embodiments, the pressure is at least 1300 kPa, preferably at least 1900 kPa. Water and other volatile matter, which may include diamine, is vented from the reactor'. The temperature of the admixture in the reactor will normally e:KCeed at Least 250°C, and especially be in the range of 1.0 270-310°C. Thai pressure in the reactor is then reduced to atmospheric pressure, especially over a period of at least IS minutes, particularly over a period of 20 to 90 minutes. The pressure should be reduced in a manner that minimizes or avcaids excessive foaming of the reaction mixture in the reactor. Anti-foam agents may be added to reduce the amount of foaming.
I~ The reaction mixhirc is then maintained at about atmospheric pressure or under a vacuum until the copolyamide has reached a predetermined molecular weight. The copolyamide thus obtained is discharged front the reactor. It should be understood, however, that the copolyamides may be subjected to solid phase polymerization or other further processing steps.
20 As is illustrated herein, the use of a polymerization process such as that described above will often result in the formation of a high melting fraction of copolyamide, with a melting point of greater than about 320°C, and especially in the range of about 330-335°C. Tht high melting fraction will normally not be apparent in the first batch of copolyamide 25 fornned in an autoclave i.e. the first batch formed after the autoclave has been thoroughly cleaned. The high melting fraction will normally appear in the second or tlurd batches of copolyamide formed in AMENDED SHEET
WO 93/23454 ~ s ~ ~ PCT/LJS93/04486 - 7 _ the autoclave. It: is not practical or economic to clean out an autoclave after each and every batch of copolyamide has been produced.
In order to prevent formation of the high melting fraction, or to at: least reduce the amount of high melting fraction t:o less than 1% by weight, and especially less than 0.01% by weight, the amount of isophthalic acid plus 2-methyl pentamethylene diamine in the aqueous solution fed to the reactor is maintained at at least 27.5% by weight, especially at least 30% by weight.
The copolyamides of the invention may be blended with stabilizers, flame retardants, smoke depressants, plasticizers, conductive and/or anti-static agents, lubricants a:nd mould release agents, nucleating agents, dyes and pigments, fillers including glass fibres, minerals, toughening and other modifying agents, and other additives that may be used in polyamide compositions. Examples of heat stabilizers include copper(I) ha:Lides e.g. bromide and iodide, and alkali halides e.g. lithium, sodium and potassium bromides and iodides, which may be used with or without phosphorus compounds. l~xamples of the latter are phosphites, phosphines, phosphates and alkali metal salts of phosphorus ac: ids e.g. sodium phenyl phosphinate, sodium hypophosphitca, triaryl- and tris(alkylaryl) phosphines e.g. tri-n-butyl p:hosphine, phenyl dimethyl phosphine and triphenyl phosphin~e. The organic heat stabilizers include hindered phenols and hindered amines, as well as W stabilizers and phenolic metal deactivators.
Nucleating agents include talc, calcium fluoride and salts of phosphorus acids, for example sodium phenyl phosphinate.
A wide range o f fillers may be used e.g. in amounts of 0.5-200 parts o:f filler per 100 parts of copolyamide.
Examples of :such fillers include, but are not limited to, silica, meta:~ilica~tes, alumina, talc, diatomaceous earth, clay, kaolin, quartz, glass, mica, titanium dioxide, RCV. t0\_E:YA 41L~,Ciilr~ ul _ __ ?5°. 5W4 _ lEi:~S : ._ __ _'3''~' .~
r:3 ;WJW'- +~i:3 F353 '>.-35J44E:5:4/1'__ _8_ molybdenum disulphide, gypsum, iron oxide, zinc oxide, fibres e.g, glass, carbon, boron, aromatic and ceramic fibres, powdered polytetrafluoroethylena; and the like.
The copolyamides may be used in the manufacture of products using melt processing techniques, especially products intended for use at temperatures that are higher than those typically used with other polyamides. >~'or exam:ple, the copolyamides may be formed into articles using injection moulding technology e.g. into valves, tanks, containers, washers and the like for automotive end-uses, into articles for electrical end~
uses e.g. parts requiring resistance to temperatures of 260°C or above, and articles where retention of mechanical properties under the influence of heat, moisture, hydrocarbons, alcohols including so-called gasohol, and the like are important. Alternatively, the polymers may be spun into fibres e.g.
for sewing or industrial threads for end-uses where low shrinkage and elongation are important and/or retention of properties under the influence of moisture, hydrocarbons, aleohols and the like ,s imporcan~.. The copolyamides may also be formed into film and sheet. Barrier properties of the copolyamides to winter and oxygen may also find uses. The copolyamides may be particularly useful for end-uses where retemion of properties at elevated temperatures is required, including as retortable containers.
The: copolya.mides ><nay be in the form of a fibre, or rilament. The fibre would preferably have a tenacity of at least I.5 gjdenier and a modules of at least g/denier.
25 The: present invention is illustrated by the following examples.
Exarr~le I
A I2L reaction vessel equipped with a helical ribbon agitator was charged with 2393.18 (14.42 moles) of terephthalie a.eid, 265.98 (1.60 moles) of isophthalic acid, 9?6g ($.41 moles) of 2-methyl 30 pentamethylene diami:ne, 1454.18 of 6?.12% (weight basis) of aqueous AMENDE~~ ~~~-~' WO 93/23454 PCf/US93/04486 _ g _ hexamethylene~ diam:ine solution (8.41 moles), 128 of 47%
(weight basis.) of <~queous sodium phenylphosphinate solution, 6m1. of 10% (weight basis) Carbowax~ 3350 polyethylene glycol in water and 11008 of demineralized water. Thus, isophthalic acid and 2-methyl pentamethylene diamine constituted 30.5% of the monomers fed to the reactor"
With ths: agitator rotating at 50 rpm, the mixture was heated to 130°C, vented to remove entrained oxygen and then heated to 224°C. With the reaction pressure maintained at: 1.90 MPa, volatile matter was released over a period of E.4 minutes, during which period of time the temperature of the reaction mixture rose to 275°C. The pressure in t:he reaction mixture was then reduced to atmospheric x>ressure over a period of 60 minutes, the temperature i.n the reaction mixture rising to 314°C. The rate of agitation was reduced to 5 rpm. The reaction mixture was mainta:fined under a vacuum of 40kPa for 15 minutes and then the polymer obtained was discharged from the reactor and quenched in a water bath.
The polymer obtained had an inherent viscosity (IV) of 0.96 dL/g; as u:~ed herein,, inherent viscosity is measured on a 5.Og,iL solution in m-cresol at 25°C
(procedure of ISO :307). The polymer had a single melting point of 289°C, as measured by differential scanning calorimetry ('DSC), a T9 of 126°C (DAM, dry as moulded), a heat deflection temperature (HDT) of 142°C (1.8 MPa, DAM) and a notched Izod impact strength of 44.6 J/m. The polymer did not exhibit the presence of a higher melting fraction.
Example II
The vessel of Example I was charged with 26598 (16.01 moles) of terephthalic acid, 10938 (9.42 moles) of 2-methyl pent:amethylene diamine, 1182.48 of 58.53%
(weight basi:~) of aqueous hexamethylene diamine solution (7.72 moles), 128 of 47% (weight basis) of aqueous sodium phenylphosphinate ;solution, 6m1 of 10% (weight basis) Carbowax~ 33..'i0 polyethylene glycol in water and 11008 of WO 93/23454 PC'T/US93/04486 - :10 -demineralized water. Copolyamide was produced using the procedure of Example I. 2-Methyl pentamethylene diamine constituted :?8.4% ~of the total monomers fed to the reactor; the reaction mixture did not contain isophthalic acid.
The copolyamide obtained had an IV of 0.68 dL/g and a melting point of 296°C. The polymer did not exhibit a high melt fraction.
Example III
Using tree procedure of Example I, a series of polymers were: prepared using different ratios of monomers. The poll~ners were checked using DSC for the presence or absences of the high melting fraction.
Tests we:re performed on unfilled polymer and on polymer filled with glass fibre.
The copolyamide compositions were moulded into test specimens using an Engel~ or a Boy injection moulding machine. The: test samples were Type I tensile bars as specified in ASTM procedure D638, and 1/4~~ and 1/8~~
(0.635 and 0.3175 c:m, respectively) flexural bars as specified in ASTM procedure D790. The specimens were moulded using a mould temperature of 80°C and an extruder barrel temperature of 320°C. Measurements were made using the following ASTM procedures: Flexural Modules -D790; Tensile Strength - D638; Notched Izod Impact Strength - D256. Melting point and heat of fusion were determined under a nitrogen atmosphere using a differential scanning calorimeter (Du Pont 912 DCDSC), at a rate of temperature rise of 10°C per minute, the temperature at the top of the endothermic curve being deemed to be the melting point. Glass transition temperature was determined by differential mechanical analysis at a rate of increase in temperature of 5°C/minute, operated under a nitrogen atmosphere.
Storage Modules is measured using the procedure of ASTM D 4065-82, Measurements are made of viscoelastic behaviour using dynamic mechanical analysis, which provides information on an elastic component, known as ~~.36177 - 1.1 -storage modulus, and on a viscous component, known as loss modulus. Mea~~urements made while the temperature is being changed lead to information on the T9 of the polymer, a heating rate of 5°C being used; data on T9 reported herein was. obtained from a plot of storage modulus against temperature, being the temperature of significant decrease in storage modulus with increasing temperature.
Further details and the results obtained are given in Table I.
WO 93/23454 PC?/US93/04486 ~~~~~. ~~7 TABLE I
Run No. 1 2 3 4 Pol er Com~osition*
Z' 50 50 47.5 45 I - - 2.5 5 HMD 25 22.5 25 25 MPMD 25 27.5 25 25 High Melting Phase yes no yes no (severe) (some) Properties -~ Un 'fled lymer Po IV (dL/g) 0.90 0.80 0.92 0.96 Tm (C) 303 293 297 289 Tensile Strength (MPa) 88.9 - 89.0 90.0 Elongation (%) - - 9 47 . Flexural Modulus (M:Pa) 3020 - 3025 2725 Notched Izod (J/m) 43 - 46 82 T (C) 125 - 123 126 H~T (1.8 MPa, C, DAM) 147 - 146 142 Properties - Fille:d Poly mer Glass fibre (wt%) 35 33 35 34 Tensile Strength (MPa) 196 167 192 207 Flexural Modulus (MPa) 9760 9200 9140 9550 Notched Izod (J/m) 80 101 91 91 HDT (1.8 MPa, C, DAM) 264 261 253 236 * T = terephthali.c acid I = isophthalic: acid HMD = hexamethylene diami.ne MPMD = 2-methyl pentamethylene diamine WO ~ ~ ~ 1 ~ ~ PCT/US93/04486 TABLE I lcont.) Run No. 5 6 7 8 9 10 Polymer Composition~t T 30 35 35 47.5 45 35 I 20 15 15 2.5 5 15 HMD 45 40 45 27.5 27.5 35 MPMD 5 10 5 22.5 22.5 15 High Melting Phase yes yes no yes yes no Tm (C) 285 293 300 303 296 298 IV (dL/g) 0.74 0.83 0.63 0.84 0.84 0.94 Thia example shows that copolyamides having a combined amount of isophthalic acid and -methyl pentamethylenc: diamine in excess of 27.5 do not exhibit the presence of high melting fraction in consecutive runs in the autoclav e. In some instances, cop olyamides having a combined amou nt of isophthalic acid and 2-methyl pentamethylenca diamine of 27.5 does show the presence of the high meltin g fraction.
The present invention relates to a process for the manufacture cf copolyamides of terephthalic acid, and especially tc the manufacture of such copolyamides without formation of a high melting fraction.
As used herein, a "single step" polymerization process is a polymerization process in which monomers are subjected to a polymerization cycle in a reactor that concludes with the pressure being returned to substantially atmospheric pressure. It is understood that the copalyamide obtained from such a process may be subjected to further processing, including finishing and extrusion, before or after pelletization.
Polymer~~ formed from terephthalic acid and diamines are known in the art. For instance, PCT patent application ~if0 92/10525 of S.L. Mok and R.U. Pagilagan, published 1952 June 25, discloses copolyamides of terephthalic acid with hexamethylene diamine and 2-methyl pentamethylene diamine, optionally containing isophthalic acid, having melting points of at least 280°C. Other polyamides of terephthalic acid are referred to therein.
Single-step polymerization processes have the advantage that polymer is manufactured in a single step, as opposed tc~ two step or multi-step processes, thereby reducing handling of the partially formed polymer during the intermed~~ate stages of the process. However, in the manufacture of copolyamides of terephthalic acid, especially copolyamides of terephthalic acid, hexamethylenea diamine and 2-methyl pentamethylene diamine, using a single step polymerization process, it has been found that a high melting fraction is formed.
The high melting fraction, with a melting point in excess of 320°C and especially approximately 334°C, is usually not noticed in the first batch of polymer produced in an autoclave, but becomes apparent in subsequent b~3tches made in the same autoclave without RCV. VOyI~YA ~1l_'~CIiE\ a 1 . _ _ ~ ='S'. 5-'~ _' ~ ~.~.43 ~ _ _ _ _ X10?
r7:3 :~85'>~ +-~9 8:3 '_:;~y94E~p : ii _8 Druckexernp~ar 2~3s~77 ~2~
steps being taken to clean-out the autoclave between consecutive batches.
As the polymer would normally be subsequently processed at melt temperatures of less than 320°C, the high melting fraction manifests itself as unmelted or gel-like portions of polymer, which are commercially unacceptable; t:ne gel-Ii:Ii;e portions arc believed to be essentially comprised of a high melting crystalline phase, which is soluble in sulphuric acid, and riot gel per sc whic:h WOLIId :not be soluble in sulphuric acid.
It ha,s now been found that copolymers of terephthalic acid, optionally including iso~phthalic acid, and mixtures of hexamethylene diarnine and 2-methyl p~entamcthylen~ diamine, may be manufactured without the formation of a high melting fraction in significant amounts.
Accordingly, the present invention provides a process for the preparation of a partially crystalline copolyamide comprising the polymerization stages of:
(a) feeding to a reactor an aqueous salt solution of an admixture of aromatic carboxylic acid and aliphatic diamine, said aromatic carboxylic acid being selected frorn the group consisting of terephthalic acid and mixtures of terephthalic; acid and isophthalic acid and said aliphatic diamine being a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine;
(b) heating the aqueous salt solution under pressure and venting water and other volatile; matter from the reactor;
(c) reducing the pressure in the reactor to atmospberie pressure;
(d) controlT,ing stages (b) and (c) so as to avoid excessive foaming of the admixture in the reactor; and (e) discharl;ing the copolyamide so obtained from the reactor;
wherein tl3e total amou nt of 2-methyl pentamethylene diamine and, when present, isopht:halic acid fed to the reactor in stage (a) is selected so that the copolyamide AMENDED SHEET
RC\ . 4U'yI.:YA \lt.W(:NE\ U 1 _ _ _ : ~~5-. 5-'J"1' _~ _ . lf'.:.'~'~ ~ _ _ _ _ 3t)'? . ~ ~ '3 ~''~'~'?" +4;3 F3:3 '?a3:3cy~~.~<~S : # _J -~~3617~
has less than 1%a by weight, based on the total amount of copolyamide, of fractions with melting lpoints greater than 320°C.
In preferred embodiments of the process of the invention, the stages of the process are controlled so that the copolyamide produced has an inherent viscosity of at least 0.6 dL/g, especially at least 0.8 dL/g.
In a further embodiment of the process of the invention, stage (c) additionally includes rroaintaining the admixture in the reactor under a vacuum.
In another embodiment, the acid and diamine are selected such that the total amount of 2-methyl pentamethylene diamine and, when present, isophthalic acid is greater than 27.5%, molar basis, especially greater than 30%, of thEe total amount of acid and diamine.
The present invention further provides in a process for the preparation of multiple: consecutive batches of a partially crystalline copolyamide of terephthalie acid and hexamethylene diamine in a reactor without clean-~~ut of the reactor, in which the copoiyamide obtained from such process contains more than 1% by weight of a fraction with a melting point of greater than 30°C, said process comprising the stages of:
(a) feeding; to a reactor an aqueous salt solution of an admixture of aromatic carboxylic .acid and aliphatic diamine, said aromatic carboxylic acid being seiectcd from the group consisting of terephthalic acid and mixtures of terephthalic acid and isophthalic acid and said aliphatic diarnine being a mixtur~: of hexa~rnethylene diamine and 2-methyl pentamethylene diamine;
(b) heating; the aqueous salt solution under pressure and venting water and other volatile: matter from the reactor;
(c) reducing the pressnrc in the reactor to atmospheric pressure;
(d) controlling stages (b) and (c) so as to avoid excessive foaming of the admixture in the reactor; and (e) dischar;giag the copolyamide so obtained from ANIEN~ED SHEEt RCV . ~ O\ _ ~Y:1 Hl; \C'lit.\ U 1 _ _ _ ~ ~'~-. S' 94 _' ~ ~~.'.'~'k' v _ _ _ __30~? .7 ~ '3 '~''~-'_ +4 9 ~3~,) '?:3;39-~~f;:i : N 10 the reactor;
the improven7:ent comprising reducing the amount of the fraction with a melting point of greater than 320°C to Less than 1% by feeding to the reactor an aqueous solution containing a total amount of 2-methyl pentamethyIene diamine and, when pr~;sent, isophthalic acid of greater than 27.5%, molar basis, of the total amount of acid and diamine.
In preferred embodiments of the process of the invention, the stages of the process are controlled so that the copolyamide produced has an inherem viscosity of at. least O.b dL/g, especially at least 0.$ dL/g.
In addition, the present invention provides in a process for the copolymerization of (1) a carboxylic acid consisting of terephthalic acid and mixtures therE;of with isophthalic acid with (2) a mixture of hexamethylene diamine and .;-methyl pentamethylene diamine, the improvement ' comprising controlling the total amount of isophthalic acid and 2-methyl pentamethyle~~e diamine so that the resultant copolyamide has less than 1%
by weight based on they total weight of the copolyamide c~f fractions having melting point'; greater than 3?0°C.
As used herein, "clean-out" of a reactor means steps takan to clean or remove high molecular weight polyamide, degradation or gel products and other matter that is not discharged from the reactor under normal processing conditions.
The; present invention relates to the manufacture of partially crystalline copolyamides formed from an aromatic carboxylic acid and a mixture of hea;amethylene diamine and 2-methyl pentamethylene dian:ine.
The aromatic carooxylic acid is terephthaiic acid or a mixture of terephthalic acid and isophthalic acid.
The: am~unt.s of acid and diamines should be substantially complernenta~y on a molar basis, as will be appreciated by persons skilled in the art. An excess of acids or diamines, especially the latter, may be used AMENDE~J ~HLE~
WO 93/23454 ~ ~ ~ PCT/US93/04486 _ 5 _ depending on 'the desired characteristics of the copolyamide a:nd the nature and extent of side reactions that may produce volatile or other matter; as noted below, diamines tend to be more volatile than acids.
The amount of isophthalic acid plus 2-methyl pentamethylene diam~ine is selected so that the copolyamide obtained has less than 1% by weight, especially less than 0.1% by weight and in particular less than 0.01% by weight, of fractions having a melting point of greater than 320°C. In preferred embodiments, the amount of isophthalic acid plus 2-methyl pentamethylene diaa~ine is selected so as to be at least 27.5%, molar basis, of the total amount of acid and diamine monomers. In more preferred embodiments, the amount of isophthal.ic acid plus 2-methyl pentamethylene diamine is at least: 30%, molar basis, of the total amount of acid and diamine~ monomers.
The copolyamicles produced by the process of the present invention acre generally partially crystalline polymers, rather than an amorphous polymer. In embodiments, the polymers have a heat of fusion of greater than 17 J/c~. Crystallinity may be determined using a differential scanning calorimeter.
The copolyamide is prepared in a polymerization process in which an aqueous salt solution of the aromatic carboxylic acids, hexamethylene diamine and 2-methyl pentamethylene diannine is fed to a reactor. The presence of 2-methyl pentamsathylene diamine appears to moderate branching that is understood to occur in a copolymer of terephthalic acid, isophthalic acid and hexamethylene diamine. The: molar amount of aromatic acid is substantially comp7lementary to the total molar amount of the diamines, as d:i.scussed above. As is known, diamines tend to be more volatile than carboxylic acids and thus it may be descirablee to feed an excess of diamine to the reactor. Cat:alyst:a may also be used e.g. phosphinic acid and/or the sodium or potassium salts thereof, phosphorus acid, hypophosphorous acid, sodium hypophosphite, RCV. VO'~_E.f'.~ ~II.WCHEV U1 _ __ ~~~5-. 5-'J'4 _:. .lE'.v.'~5 v _ __ __3lW ~
r3 aH5:1-. +.~y f3:3 '?.35~441iS:bl1 ~~.36177 ~6-phospborie acid and the; like; typical amounts of catalysts arc 0.05-L00%'o by weight, especially 0.10-0.20% by weight.
In the process, the aqueous salt solution is heated in a reactor (autoclave) under pressure. The actual pressure used will depend in part on the particular copolyarnidc that is to be produced in the process. In preferred embodiments, the pressure is at least 1300 kPa, preferably at least 1900 kPa. Water and other volatile matter, which may include diamine, is vented from the reactor'. The temperature of the admixture in the reactor will normally e:KCeed at Least 250°C, and especially be in the range of 1.0 270-310°C. Thai pressure in the reactor is then reduced to atmospheric pressure, especially over a period of at least IS minutes, particularly over a period of 20 to 90 minutes. The pressure should be reduced in a manner that minimizes or avcaids excessive foaming of the reaction mixture in the reactor. Anti-foam agents may be added to reduce the amount of foaming.
I~ The reaction mixhirc is then maintained at about atmospheric pressure or under a vacuum until the copolyamide has reached a predetermined molecular weight. The copolyamide thus obtained is discharged front the reactor. It should be understood, however, that the copolyamides may be subjected to solid phase polymerization or other further processing steps.
20 As is illustrated herein, the use of a polymerization process such as that described above will often result in the formation of a high melting fraction of copolyamide, with a melting point of greater than about 320°C, and especially in the range of about 330-335°C. Tht high melting fraction will normally not be apparent in the first batch of copolyamide 25 fornned in an autoclave i.e. the first batch formed after the autoclave has been thoroughly cleaned. The high melting fraction will normally appear in the second or tlurd batches of copolyamide formed in AMENDED SHEET
WO 93/23454 ~ s ~ ~ PCT/LJS93/04486 - 7 _ the autoclave. It: is not practical or economic to clean out an autoclave after each and every batch of copolyamide has been produced.
In order to prevent formation of the high melting fraction, or to at: least reduce the amount of high melting fraction t:o less than 1% by weight, and especially less than 0.01% by weight, the amount of isophthalic acid plus 2-methyl pentamethylene diamine in the aqueous solution fed to the reactor is maintained at at least 27.5% by weight, especially at least 30% by weight.
The copolyamides of the invention may be blended with stabilizers, flame retardants, smoke depressants, plasticizers, conductive and/or anti-static agents, lubricants a:nd mould release agents, nucleating agents, dyes and pigments, fillers including glass fibres, minerals, toughening and other modifying agents, and other additives that may be used in polyamide compositions. Examples of heat stabilizers include copper(I) ha:Lides e.g. bromide and iodide, and alkali halides e.g. lithium, sodium and potassium bromides and iodides, which may be used with or without phosphorus compounds. l~xamples of the latter are phosphites, phosphines, phosphates and alkali metal salts of phosphorus ac: ids e.g. sodium phenyl phosphinate, sodium hypophosphitca, triaryl- and tris(alkylaryl) phosphines e.g. tri-n-butyl p:hosphine, phenyl dimethyl phosphine and triphenyl phosphin~e. The organic heat stabilizers include hindered phenols and hindered amines, as well as W stabilizers and phenolic metal deactivators.
Nucleating agents include talc, calcium fluoride and salts of phosphorus acids, for example sodium phenyl phosphinate.
A wide range o f fillers may be used e.g. in amounts of 0.5-200 parts o:f filler per 100 parts of copolyamide.
Examples of :such fillers include, but are not limited to, silica, meta:~ilica~tes, alumina, talc, diatomaceous earth, clay, kaolin, quartz, glass, mica, titanium dioxide, RCV. t0\_E:YA 41L~,Ciilr~ ul _ __ ?5°. 5W4 _ lEi:~S : ._ __ _'3''~' .~
r:3 ;WJW'- +~i:3 F353 '>.-35J44E:5:4/1'__ _8_ molybdenum disulphide, gypsum, iron oxide, zinc oxide, fibres e.g, glass, carbon, boron, aromatic and ceramic fibres, powdered polytetrafluoroethylena; and the like.
The copolyamides may be used in the manufacture of products using melt processing techniques, especially products intended for use at temperatures that are higher than those typically used with other polyamides. >~'or exam:ple, the copolyamides may be formed into articles using injection moulding technology e.g. into valves, tanks, containers, washers and the like for automotive end-uses, into articles for electrical end~
uses e.g. parts requiring resistance to temperatures of 260°C or above, and articles where retention of mechanical properties under the influence of heat, moisture, hydrocarbons, alcohols including so-called gasohol, and the like are important. Alternatively, the polymers may be spun into fibres e.g.
for sewing or industrial threads for end-uses where low shrinkage and elongation are important and/or retention of properties under the influence of moisture, hydrocarbons, aleohols and the like ,s imporcan~.. The copolyamides may also be formed into film and sheet. Barrier properties of the copolyamides to winter and oxygen may also find uses. The copolyamides may be particularly useful for end-uses where retemion of properties at elevated temperatures is required, including as retortable containers.
The: copolya.mides ><nay be in the form of a fibre, or rilament. The fibre would preferably have a tenacity of at least I.5 gjdenier and a modules of at least g/denier.
25 The: present invention is illustrated by the following examples.
Exarr~le I
A I2L reaction vessel equipped with a helical ribbon agitator was charged with 2393.18 (14.42 moles) of terephthalie a.eid, 265.98 (1.60 moles) of isophthalic acid, 9?6g ($.41 moles) of 2-methyl 30 pentamethylene diami:ne, 1454.18 of 6?.12% (weight basis) of aqueous AMENDE~~ ~~~-~' WO 93/23454 PCf/US93/04486 _ g _ hexamethylene~ diam:ine solution (8.41 moles), 128 of 47%
(weight basis.) of <~queous sodium phenylphosphinate solution, 6m1. of 10% (weight basis) Carbowax~ 3350 polyethylene glycol in water and 11008 of demineralized water. Thus, isophthalic acid and 2-methyl pentamethylene diamine constituted 30.5% of the monomers fed to the reactor"
With ths: agitator rotating at 50 rpm, the mixture was heated to 130°C, vented to remove entrained oxygen and then heated to 224°C. With the reaction pressure maintained at: 1.90 MPa, volatile matter was released over a period of E.4 minutes, during which period of time the temperature of the reaction mixture rose to 275°C. The pressure in t:he reaction mixture was then reduced to atmospheric x>ressure over a period of 60 minutes, the temperature i.n the reaction mixture rising to 314°C. The rate of agitation was reduced to 5 rpm. The reaction mixture was mainta:fined under a vacuum of 40kPa for 15 minutes and then the polymer obtained was discharged from the reactor and quenched in a water bath.
The polymer obtained had an inherent viscosity (IV) of 0.96 dL/g; as u:~ed herein,, inherent viscosity is measured on a 5.Og,iL solution in m-cresol at 25°C
(procedure of ISO :307). The polymer had a single melting point of 289°C, as measured by differential scanning calorimetry ('DSC), a T9 of 126°C (DAM, dry as moulded), a heat deflection temperature (HDT) of 142°C (1.8 MPa, DAM) and a notched Izod impact strength of 44.6 J/m. The polymer did not exhibit the presence of a higher melting fraction.
Example II
The vessel of Example I was charged with 26598 (16.01 moles) of terephthalic acid, 10938 (9.42 moles) of 2-methyl pent:amethylene diamine, 1182.48 of 58.53%
(weight basi:~) of aqueous hexamethylene diamine solution (7.72 moles), 128 of 47% (weight basis) of aqueous sodium phenylphosphinate ;solution, 6m1 of 10% (weight basis) Carbowax~ 33..'i0 polyethylene glycol in water and 11008 of WO 93/23454 PC'T/US93/04486 - :10 -demineralized water. Copolyamide was produced using the procedure of Example I. 2-Methyl pentamethylene diamine constituted :?8.4% ~of the total monomers fed to the reactor; the reaction mixture did not contain isophthalic acid.
The copolyamide obtained had an IV of 0.68 dL/g and a melting point of 296°C. The polymer did not exhibit a high melt fraction.
Example III
Using tree procedure of Example I, a series of polymers were: prepared using different ratios of monomers. The poll~ners were checked using DSC for the presence or absences of the high melting fraction.
Tests we:re performed on unfilled polymer and on polymer filled with glass fibre.
The copolyamide compositions were moulded into test specimens using an Engel~ or a Boy injection moulding machine. The: test samples were Type I tensile bars as specified in ASTM procedure D638, and 1/4~~ and 1/8~~
(0.635 and 0.3175 c:m, respectively) flexural bars as specified in ASTM procedure D790. The specimens were moulded using a mould temperature of 80°C and an extruder barrel temperature of 320°C. Measurements were made using the following ASTM procedures: Flexural Modules -D790; Tensile Strength - D638; Notched Izod Impact Strength - D256. Melting point and heat of fusion were determined under a nitrogen atmosphere using a differential scanning calorimeter (Du Pont 912 DCDSC), at a rate of temperature rise of 10°C per minute, the temperature at the top of the endothermic curve being deemed to be the melting point. Glass transition temperature was determined by differential mechanical analysis at a rate of increase in temperature of 5°C/minute, operated under a nitrogen atmosphere.
Storage Modules is measured using the procedure of ASTM D 4065-82, Measurements are made of viscoelastic behaviour using dynamic mechanical analysis, which provides information on an elastic component, known as ~~.36177 - 1.1 -storage modulus, and on a viscous component, known as loss modulus. Mea~~urements made while the temperature is being changed lead to information on the T9 of the polymer, a heating rate of 5°C being used; data on T9 reported herein was. obtained from a plot of storage modulus against temperature, being the temperature of significant decrease in storage modulus with increasing temperature.
Further details and the results obtained are given in Table I.
WO 93/23454 PC?/US93/04486 ~~~~~. ~~7 TABLE I
Run No. 1 2 3 4 Pol er Com~osition*
Z' 50 50 47.5 45 I - - 2.5 5 HMD 25 22.5 25 25 MPMD 25 27.5 25 25 High Melting Phase yes no yes no (severe) (some) Properties -~ Un 'fled lymer Po IV (dL/g) 0.90 0.80 0.92 0.96 Tm (C) 303 293 297 289 Tensile Strength (MPa) 88.9 - 89.0 90.0 Elongation (%) - - 9 47 . Flexural Modulus (M:Pa) 3020 - 3025 2725 Notched Izod (J/m) 43 - 46 82 T (C) 125 - 123 126 H~T (1.8 MPa, C, DAM) 147 - 146 142 Properties - Fille:d Poly mer Glass fibre (wt%) 35 33 35 34 Tensile Strength (MPa) 196 167 192 207 Flexural Modulus (MPa) 9760 9200 9140 9550 Notched Izod (J/m) 80 101 91 91 HDT (1.8 MPa, C, DAM) 264 261 253 236 * T = terephthali.c acid I = isophthalic: acid HMD = hexamethylene diami.ne MPMD = 2-methyl pentamethylene diamine WO ~ ~ ~ 1 ~ ~ PCT/US93/04486 TABLE I lcont.) Run No. 5 6 7 8 9 10 Polymer Composition~t T 30 35 35 47.5 45 35 I 20 15 15 2.5 5 15 HMD 45 40 45 27.5 27.5 35 MPMD 5 10 5 22.5 22.5 15 High Melting Phase yes yes no yes yes no Tm (C) 285 293 300 303 296 298 IV (dL/g) 0.74 0.83 0.63 0.84 0.84 0.94 Thia example shows that copolyamides having a combined amount of isophthalic acid and -methyl pentamethylenc: diamine in excess of 27.5 do not exhibit the presence of high melting fraction in consecutive runs in the autoclav e. In some instances, cop olyamides having a combined amou nt of isophthalic acid and 2-methyl pentamethylenca diamine of 27.5 does show the presence of the high meltin g fraction.
Claims (12)
1. A process for the preparation of a partially crystalline copolyamide comprising the polymerization stages of:
(a) feeding to a reactor an aqueous salt solution of an admixture of aromatic carboxylic acid and aliphatic diamine, said aromatic carboxylic acid being selected from the group consisting of terephathalic acid and mixtures of terephthalic acid and isophthalic acid and said aliphatic diamine being a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine, wherein the acid and diamine are selected such that the combined amount of isophthalic acid and 2-methyl pentamethylene diamine is greater than 27.5%, molar basis, of the total amount of acid and diamine;
(b) heating the aqueous salt solution under pressure and venting water and other volatile matter from the reactor;
(c) reducing the pressure in the reactor to atmospheric pressure;
(d) controlling stages (b) and (c) so as to avoid excessive foaming of the admixture in the reactor; and (e) discharging the copolyamide so obtained from the reactor; wherein the total amount of 2-methyl pentamethylene diamine and, when present, isophthalic acid fed to the reactor in stage (a) is selected so that the copolyamide has less than 1% by weight, based on the total amount of copolyamide, of fractions with melting points greater than 320°C.
(a) feeding to a reactor an aqueous salt solution of an admixture of aromatic carboxylic acid and aliphatic diamine, said aromatic carboxylic acid being selected from the group consisting of terephathalic acid and mixtures of terephthalic acid and isophthalic acid and said aliphatic diamine being a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine, wherein the acid and diamine are selected such that the combined amount of isophthalic acid and 2-methyl pentamethylene diamine is greater than 27.5%, molar basis, of the total amount of acid and diamine;
(b) heating the aqueous salt solution under pressure and venting water and other volatile matter from the reactor;
(c) reducing the pressure in the reactor to atmospheric pressure;
(d) controlling stages (b) and (c) so as to avoid excessive foaming of the admixture in the reactor; and (e) discharging the copolyamide so obtained from the reactor; wherein the total amount of 2-methyl pentamethylene diamine and, when present, isophthalic acid fed to the reactor in stage (a) is selected so that the copolyamide has less than 1% by weight, based on the total amount of copolyamide, of fractions with melting points greater than 320°C.
2. The process of Claim 1 in which the stages of the process are controlled so that the copolyamide produced has an inherent viscosity of at least 0.6 dL/g.
3. The process of Claim 2 in which the copolyamide has an inherent viscosity of at least 0.8 dL/g.
4. The process of any one of Claim 1-3 in which stage (c) additionally includes maintaining the admixture in the reactor under a vacuum.
5. The process of any one of Claims 1-4 in which the acid and diamine are selected such that the total amount of 2-methyl pentamethylene diamine and, when present, isophthalic acid is greater than 30%, molar basis, of the total amount of acid and diamine.
6. The process of any one of Claims 1-5 in which the copolyamide has less than 0.1% by weight of the fraction with a melting point of greater than 320°C.
7. The process of any one of Claims 1-5 in which the copolyamide has less than 0.01% by weight of the fraction with a melting point of greater than 320°C.
8. In a process for the preparation of multiple consecutive batches of a partially crystalline copolyamide of terephthalic acid and hexamethylene diamine in a reactor without clean-out of the reactor, in which the copolyamide obtained from such process contains more than 1% by weight of a fraction with a melting point of greater than 320°C, said process comprising the stages of:
(a) feeding to a reactor an aqueous salt solution of an admixture of aromatic carboxylic acid and aliphatic diamine, said aromatic carboxylic acid being selected from the group consisting of terephthalic acid and mixtures of terephthalic acid and isophthalic acid and said aliphatic diamine being a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine;
(b) heating the aqueous salt solution under pressure and venting water and other volatile matter from the reactor, (c) reducing the pressure in the reactor to atmospheric pressure;
(d) controlling stages (b) and (c) so as to avoid excessive foaming of the admixture in the reactor; and (e) discharging the copolyamide so obtained from the reactor;
the improvement comprising reducing the amount of the fraction with a melting point of greater than 320°C to less than 1% by feeding to the reactor an aqueous solution containing a total amount of 2-methyl pentamethylene diamine and, when present, isophthalic acid of greater than 27.5%, molar basis, of the total amount of acid and diamine.
(a) feeding to a reactor an aqueous salt solution of an admixture of aromatic carboxylic acid and aliphatic diamine, said aromatic carboxylic acid being selected from the group consisting of terephthalic acid and mixtures of terephthalic acid and isophthalic acid and said aliphatic diamine being a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine;
(b) heating the aqueous salt solution under pressure and venting water and other volatile matter from the reactor, (c) reducing the pressure in the reactor to atmospheric pressure;
(d) controlling stages (b) and (c) so as to avoid excessive foaming of the admixture in the reactor; and (e) discharging the copolyamide so obtained from the reactor;
the improvement comprising reducing the amount of the fraction with a melting point of greater than 320°C to less than 1% by feeding to the reactor an aqueous solution containing a total amount of 2-methyl pentamethylene diamine and, when present, isophthalic acid of greater than 27.5%, molar basis, of the total amount of acid and diamine.
9. The process of Claim 8 in which the stages of the process are controlled so that the copolyamide produced has an inherent viscosity of at least 0.6 dL/g.
10. The process of Claim 9 in which the copolyamide has an inherent viscosity of at least 0.8 dL/g.
11. In a process for the copolymerization of (1) a carboxylic acid consisting of terephthalic acid and mixtures thereof with isophthalic acid with (2) a mixture of hexamethylene diamine and 2-methyl pentamethylene diamine, wherein the combined amount of isophthalic acid and 2-methyl pentamethylene diamine is greater than 27.5%, molar basis, of the total amount of acid and diamine, the improvement comprising controlling the total amount of isophthalic acid and 2-methyl pentamethylene diamine so that the resultant copolyamide has less than 1% by weight based on the total weight of the copolyamide of fractions having melting points greater than 320°C.
12. The process of Claim 11 in which the acid acid diamine are selected such that the total amount of isophtalic acid and 2-methyl pentamethylene diamine is greater than 30%, molar basis, of the total amount of acid and diamine.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/885,330 US5302691A (en) | 1992-05-19 | 1992-05-19 | Manufacture of terephthalic acid/2-methylpentamethylene diamine/hexamethylene diamine copolyamides |
| US07/885,330 | 1992-05-19 | ||
| PCT/US1993/004486 WO1993023454A1 (en) | 1992-05-19 | 1993-05-18 | Manufacture of terephthalic acid copolyamides |
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| Publication Number | Publication Date |
|---|---|
| CA2136177A1 CA2136177A1 (en) | 1993-11-25 |
| CA2136177C true CA2136177C (en) | 2005-03-15 |
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| CA002136177A Expired - Lifetime CA2136177C (en) | 1992-05-19 | 1993-05-18 | Manufacture of terephthalic acid copolyamides |
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|---|---|
| US (1) | US5302691A (en) |
| EP (1) | EP0641365A1 (en) |
| JP (1) | JPH07508064A (en) |
| AU (1) | AU4246093A (en) |
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| GB202115260D0 (en) | 2021-10-22 | 2021-12-08 | Invista Textiles Uk Ltd | Process for consecutive batch production of polyamide |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2542938A1 (en) * | 1975-09-26 | 1977-04-07 | Dynamit Nobel Ag | TRANSPARENT POLYAMIDE |
| DE2627342A1 (en) * | 1976-06-18 | 1977-12-22 | Dynamit Nobel Ag | PROCESS FOR PRODUCTION OF POSSIBLY MODIFIED POLY- (ALKYLPENTAMETHYLENE TEREPHTHALAMIDE) |
| FR2643377B1 (en) * | 1989-02-21 | 1992-09-11 | Rhone Poulenc Chimie | PROCESS FOR THE PREPARATION OF SEMI-AROMATIC POLYAMIDES COMPRISING RESIDUES OF AROMATIC DICARBOXYLIC ACID (S) AND ALKYLPENTAMETHYLENEDIAMINE |
| WO1991000442A1 (en) * | 1989-07-03 | 1991-01-10 | Bernhard Rohland | Improvement in a pressing tool |
| FR2660316B1 (en) * | 1990-03-30 | 1994-03-11 | Rhone Poulenc Chimie | SEMI-AROMATIC SEMI-CRYSTALLINE COPOLYAMIDES OBTAINED FROM TEREPHTHALIC ACID AND MIXTURES COMPRISING ALKYLPENTAMETHYLENEDIAMINE AND HEXAMETHYLENEDIAMINE. |
| JPH06503590A (en) * | 1990-12-12 | 1994-04-21 | デユポン・カナダ・インコーポレーテツド | Terephthalic acid copolyamide |
-
1992
- 1992-05-19 US US07/885,330 patent/US5302691A/en not_active Expired - Lifetime
-
1993
- 1993-05-18 WO PCT/US1993/004486 patent/WO1993023454A1/en not_active Application Discontinuation
- 1993-05-18 AU AU42460/93A patent/AU4246093A/en not_active Abandoned
- 1993-05-18 CA CA002136177A patent/CA2136177C/en not_active Expired - Lifetime
- 1993-05-18 JP JP6503713A patent/JPH07508064A/en active Pending
- 1993-05-18 EP EP93911264A patent/EP0641365A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| WO1993023454A1 (en) | 1993-11-25 |
| AU4246093A (en) | 1993-12-13 |
| JPH07508064A (en) | 1995-09-07 |
| US5302691A (en) | 1994-04-12 |
| EP0641365A1 (en) | 1995-03-08 |
| CA2136177A1 (en) | 1993-11-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request |